Railway traffic controlling apparatus



. B. E. O'HAGAN RAILWAY TRAFFIC CONTROLLING APPARATUS July 18, 1939.

OPERATING MECHANLSM Filed Dec. 16, 1937 5 m m w G M W P 1| M N HTm d 0 wr 0 HIS ATTORNEY Patented July 18, 1939 UNITED STATES PATENT OFFICERAILWAY TRAFFIC CONTROLLING APPARATUS Application December 16, 1937,Serial No. 180,182

8 Claims.

My invention relates to railway traflic controlling apparatus, and hasfor an object the provision of novel and improved apparatus for theprotection of a railway switch operating motor against overloadconditions.

I shall describe two forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

Figs. 1 and 2 of the accompanying drawing 'are diagrammatic views of twoforms of apparatus, each form of which embodies my invention." Similarreference characters refer to similar parts in each of the two views.

Referring to Fig. l, the reference character S designates a railwaytrack switch which is actuated by an electric motor M through the mediumof a suitable switch operating mechanism SM, the motor M being hereshown as a direct current reversible motor having an armature 3 and afield winding 4. The switch operating mechanism SM may be of any of thestandard types, and is shown conventionally for the sake of simplicity.The switch S operates a circuit controller H through the medium of anysuitable connection indicated by a dash line 35. The controller Hcomprises two movable contact members 5 and 6, the contact member 5being arranged to make engagement with a contact! at all positions ofthe switch S except the full normal position, that is, the positionillustrated in Fig. l; and the contact member 6 being arranged to makeengagement with a contact 8 at all positions of the switch except thefull reverse position, that is, the position opposite that shown in Fig.l.

The motor M is reversibly operated by a normal and a reverse operatingcircuit, which circuits are governed by a contactor CT comprising adirect current normal magnet N and a reverse magnet B. When the normalmagnet N is energized and picked up in a manner to later appear, thenormal motor operating circuit is formed from the B terminal of anyconvenient source of current, such as a battery not shown, over frontcontact I! of the normal magnet N, motor armature 3, back contact I8 ofthe reverse magnet R, field winding 4, a resistor R2 to be referred tolater, and to the C terminal of the current source. The flow of currentset up by this normal .motor circuit in the motor armature 3 and fieldwinding 4 is of such direction as to cause the .motor to operate in thedirection that moves the jtrack switch to its normal position. With thereverse magnet R energized and picked. up, the reverse motor operatingcircuit is formed from terminal B over front contact I9 of the reversemagnet R, motor armature 3, back contact of normal magnet N, fieldwinding 4, resistor R2, and to the C terminal. The direction of the flowof current in the motor armature 3 is now reversed and the motor isoperated in a direction as required to move the track switch to itsreverse position.

The contactor magnets N and R are controlled by means of a manuallyoperated device or lever L, which may be located at any convenientpoint, such as an operators orifice remote from the track switch. Thelever L may be a switch lever of an interlocking machine. The lever L isoperated to a normal or left-hand position as indicated by the fulllines in Fig. l, and to a reverse or right-hand position as indicated bya dotted line in Fig. 1. A circuit controlling contact member 9 isactuated by the lever L, the arrangement being such that the contactmember 9 engages a contact It at the normal position of the lever L, andengages a contact II at the reverse position of the lever. It is to benoted that the contact member 9 might be a polar contact finger of apolar relay, which relay in turn is controlled over pole changingcontacts actuated by the lever L.

The control of the contactor magnets N and R by the lever L is effectedover a normal and a reverse control circuit. The normal control circuitcan be traced from the B terminal of any convenient source of current,contact 9-Hi of lever L in' its normal position, normal control wire 12,contact 5-7 of controller H when closed, wire l3, winding 33 of magnetN, wire 54, back contact I5 of an overload relay OR to be describedlater, and a common return wire 36 to the terminal C of the same sourceof current. The reverse control circuit extends from terminal B overcontact 9-I i of lever L in its reverse position, reverse control wire38, Contact 68 of controller H, wire 24, winding 33 of reverse magnet R,wire it, back contact E5 of relay OR, and the common return wire 36 tothe C terminal. A resistor RI is connected across these two controlcircuits by being connected between the wires l3 and 24 adjacent theoutside terminals of the windings 33 and 34 of the normal and reversemagnets respectively, as will be readily understood by an inspection ofthe drawing. The function of resistor RI will be described later on inthe specification.

It follows that, with the lever L operated to its reverse position, whenthe switch S is normal closing controller contact 5-8, the reversecontactor magnet R is energized and picked up to close the reverseoperating circuit and the switch is moved to its reverse position. Atthe full reverse position the contact 6-8 is opened to cause the magnetR to be deenergized and released, opening the reverse motor operatingcircuit. With the lever L moved to its normal position, when the switchis in its reverse position, closing controller contact 7, the normalmagnet N is energized and picked up to complete the normal motor circuitso that the switch is moved to its normal position. At the full normalposition the contact 5-? is operated to an open position so that magnetN is deenergized and released to open the motor operating circuit. Withthe switch in mid-stroke position so that both contacts 5'I and i3S areclosed, then the magnets N and R are selected according to the positionof the lever L to cause corresponding operation of the motor.

An auxiliary or overload relay OR is associated with the switchoperating circuits for protection of the motor M under overloadconditions. The overload relay OR is a direct current neutral relayprovided with a single operating winding 2|. The resistor R2, which iscommon to both motor operating circuits, is disposed in the motoroperating circuits in multiple with the winding 2| of the overload relayOR, one terminal of winding 2i being connected with one terminal ofresistor R2 over a back contact 22 and transfer contact 23 of the relayOR, and the other terminal of winding 2! being connected with the otherterminal of resistor OR over a wire 31. The resistor R2 is preferablyconstructed of material having a relatively high positive temperaturecoeflicient of resistance such as nickel or iron. The resistor R2 andthe overload relay OR are so constructed and proportioned that, when themotor current flowing in resistor R2 and winding 2| in multiple does notexceed that required to operate the motor and in turn the track switch Sunder usual operating conditions, the potential drop across resistor R2is relatively low and the energization of winding 2! is insufiicient topick up the relay OR. However, under overload conditions such as occursin the event the track switch S is obstructed the motor current isrelatively large and the resistor R2 quickly heats up to materiallyincrease its resistance so that the potential drop across the resistorR2 soon exceeds a predetermined value and the winding 2| of relay OR isenergized sufficiently to cause the relay to be picked up. The parts arefurther so proportioned that surges of current, which are high in valuebut of relatively short duration, such as starting and reversal surges,are not effective to pick up the relay OR. Furthermore, the relay OR ispreferably provided with slow-topick-up characteristics and does notrespond to short durations of relatively high energizing current createdby starting and reversal surges of current. The relay OR on picking upto open its back contact I5 opens the connection of the contactor magnetN or R, as the case may be, to the common return wire 36, and thecontactor magnet is deenergized and released to open the overloadedmotor circuit. That is, the contactor magnet N is released to open thenormal motor circuit at front contact I! if the overload occurs during amovement of the switch to the normal position, and the contactor magnetR is released to open the reverse motor circuit at front contact I9 ifthe overload occurs during a movement of the switch to the reverseposition.

The overload relay OR is provided with a normal and a reverse stickcircuit by which it is rea;- tained energized subsequent to an overloadcon- .dition on a motor operating circuit that causes the overload relayto be picked up. Assuming the lever L has been moved to its reverseposition, closing contact 9-I I to complete the reverse control circuitso that magnet R is picked up and the motor is operated to move theswitch to its reverse position, and an overload occurs which causes therelay OR to be picked up,- a reverse stick circuit for relay OR can betraced from terminal B, contact 9-I I, control wire 38, contact 68, wire24, through the right-hand portion of resistor RI to a mid terminal,wire 25, front contact 26 and transfer contact 23 of relay OR, winding2| of relay OR, wire 31, common re-- turn wire 36 and to the C terminal.event the lever L has been operated to its normal position, closingcontact 9-40 to complete the normal control circuit so that magnet N ispicked up and the motor operated to move the switch to its normalposition, and an overload condition occurs which causes relay OR to pickup, a normal stick circuit is formed from terminal B over contact 9-),control wire l2, contact 5'I, wire I3, left-hand portion of resistor RIto its mid terminal, wire 25, front contact 26 and transfer contact 23of relay OR, Winding 2|, wire 31, and the common return wire 36 to the Cterminal. It follows that an overload condition that causes relay OR tobe picked up to open the overloaded motor circuit also switches thewinding 2| of the overload relay from the motor operating circuit to thecontrol circuit active at the time of the overload, with the result thatthe relay OR is retained picked up subsequent to the overload conditionto hold the overloaded circuit open, selection between the normal andreverse control circuits being effected through the medium of theresistor RI.

To regain control of the motor subsequent to an overload condition andthe relay OR is held energized by virtue of its stick circuit, theoperator must actuate the lever L to the position opposite that at whichthe overload condition occurred. Assuming the lever L is at its reverseposition and relay OR is held energized over its reverse stick circuitincluding the contact 9-I I, control wire 38 and the right-hand portionof resistor RI, the operator would move the lever L to its normalposition where the contact 9-II is open. The relay OR is now deenergizedand released, closing back contact I5 interposed in the connection ofmagnet N with the common return wire 36. With magnet N thus energizedand picked up, the motor M is operated to move the switch back to thenormal position, that is, the position it occupied prior to the overloadcondition. Again, if the lever L is at its normal position and relay ORis picked up in response to an overload condition and held energized byits normal stick circuit, the operator would move the lever L to itsreverse position where the relay OR is deenergized since the normalstick circuit is now open at contact 9I0.

In this connection, it is to be pointed out that overload relay OR isadjusted for relatively quick release, and release of the relay duringmovement of the lever L from one position to the other is assured. Also,the resistor RI is preferably proportioned for relatively highresistance so that the energization of the overload relay OR by eitherof its stick circuits is not much greater than the release value of therelay, and release of .the relay in response to a movement of the leverL'is quickly effected.

With the resistor RI proportioned for rela- In the (ill tively highresistance, the picking up of both contactor magnets N and R at eitherposition of lever L is avoided, and the release of each contactor magnetwhen the lever is moved from one position to the other is assured. To beexplicit, the current which flows, when the lever is at its reverseposition, from wire 24 through both portions of resistor RI, winding 33of contactor magnet N, wire I4, and back contact l5 to the common returnwire, is not sufiicient to energize the normal magnet N. When the leverL is moved to its normal position, the current which flows from wire I3through resistor RI, winding 35' of ma gnet R, wire I 4, and backcontact l5 to the common return wire 36, is not nearly sufficient topick up the reverse contactor magnet R.

In Fig. 2, the apparatus is the same as in Fig. 1, except that twoseparate resistors R3 and R4 are used in place of the resistor R! andthe relay OR is provided with additional contacts. The resistors R3 andR4 are interposed in the normal and reverse stick circuits for the relayOR, respectively. Assuming the lever L is in its normal position andrelay OR is picked up in response to an overload, the normal stickcircuit in Fig. volves terminal B, contact 9l!l, wire l2, contact 5-1,wire l3, resistor R3, wire 27, front contact 28 and transfer contact 29of relay OR, winding 2! of relay OR, wire 3'! and common return wire 35to the C terminal. The reverse stick circuit involves terminal B,contact 9-! i, wire 28, con tact 6-8, wire 24, resistor R4, wire 36,front con tact 3| and transfer contact 32 of relay OR, winding 2! of therelay, wire 3? and common return wire 36 to the C terminal.

It is clear that the operation of the apparatus of Fig. 2 issubstantially the as the I eration of the apparatus of Fig. 1, and it isthought to be unnecessary to repeat the operation except to point outthat in Fig. 2 there is no leakage current through the winding 33 ofcontactor magnet N when the lever is at its reverse position to energizecontactor magnet R, and there is no leakage current through the winding34 of contactor magnet B when the lever is moved to its normal position.

Although I have herein shown and described only two forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a reversible electric motor, a normal and a reverseoperating circuit for the motor, a normal and a reverse control circuitfor governing said normal and reverse operating circuits respectively,said control circuits each comprising a control wire and a common wireas well as a circuit controlling contact, a resistor common to both ofsaid motor circuits, a relay having a winding connected across saidresistor, said relay and resistor proportioned and adjusted to pick upsaid relay only when an overload current flows through said resistor fora predetermined interval, means controlled by said relay when picked upto interrupt the overloaded motor circuit, a normal stick circuit forsaid overload relay including the control Wire and circuit controllingcontact as well as the common wire of the normal control circuit, and areverse stick circuit for said relay including the control wire andcircuit controlling contact as well as the common wire of the reversecontrol circuit.

2. In combination, a reversible electric motor, an operating circuitmeans for said motor, a contactor including a normal and a reversemagnet for governing said operating circuit means, a normal controlcircuit including a pair of control Wires and a circuit controllingcontact as well as a winding of said normal magnet, a reverse controlcircuit including a pair of control Wires and a circuit controllingcontact as well as a winding of said reverse magnet, a resistorinterposed in said operating circuit means, a relay, means to connect awinding of the relay across the resistor to pick up the relay when andonly when an overload current flows in the motor for a predeterminedinterval, means controlled by the relay when picked up to interrupt theoperating circuit means, a normal stick: circuit to connect the windingof said reiay across said control wires of the normal control circuitincluding a front contact of the relay and a resistance, and a reversestick circuit to connect the winding of said relay across said controlwires of the reverse control circuit including a front contact of therelay and a resistance.

3. In combination, a reversible electric motor,

a normal and a reverse operating circuit for said motor, a normal and areverse direct cur rent neutral magnet for governing said normal andreverse operating circuits respectively, a normal control circuitincluding a normal control a;

wire connected to one terminal of the winding of the normal magnet and acommon wire connected to the other terminal of the magnet winding, areverse control circuit including a reverse control wire connected withone terminal of the winding of the reverse magnet and said common wireconnected to the other terminal of the magnet wlnding, means including acontact member to selectively connect a current source with said controlcircuits to energize either the normal or reverse magnets, a resistorcommon to both of said motor circuits, a relay, means including a backcontact of the relay to connect the winding of said relay across saidresistor to pick up the relay when an overload current flows in saidmotor, a back contact of said relay interposed in the connection of thewinding of each of said magnets with the common wire to cause anoverloaded motor circuit to be interrupted, a normal stick circuit toconnect the winding of said relay across said normal control wire. andthe common wire, and a reverse stick circuit to connect the winding ofthe relay across said reverse control wire and the common wire.

4. In combination, a reversible electric motor,

a normal and a reverse magnet, a normal motor operating circuitincluding a front contact of the normal magnet, a reverse motoroperating circuit including a front contact of the reverse magnet, anormal control circuit including a nor- U mal control wire connected tothe outside terminal of the winding of the normal magnet and a commonwire connected to the inside terminal of the magnet winding, 2. reversecontrol circuit including a reverse control wire connected with theoutside terminal of the winding of the reverse magnet .and said commonwire connected with the inside terminal of the magnet winding, a firstresistor connected across the outside terminals of the magnet windings,a second resistor common to both motor circuits, a relay, meansincluding a back contact of the relay to connect the winding of saidrelay across said second resistor to pick up the relay when an overloadcurrent flows in the motor for a given interval, a

back contact of said relay interposed in the connections of the magnetwindings with the common wire to release a magnet for interrupting anoverloaded motor circuit, and a stick circuit means to connect thewinding of the relay between the common wire and a mid terminal of saidfirst resistor.

5, In combination, a reversible electric motor, a normal and a reversemagnet, a normal motor operating circuit including a front contact ofthe normal magnet, a reverse motor operating circuit including a frontcontact of the reverse magnet, an overload relay, a normal control wireconnected with the inside terminal of the winding of the normal magnet,a reverse control wire connected with the inside terminal of the windingof the reverse magnet, means including a back contact of the relay toconnect the outside terminal of each of said windings with a commonreturn wire, a circuit controller operative to connect a direct currentsource between either the normal or reverse control wire and the commonwire, means including a back contact of the relay to associate thewinding of the relay with both of said motor operating circuits to pickup the relay when an overload current fiows in the motor to deenergizethe magnet for interrupting the overloaded circuit, a resistor connectedbetween the said inside terminals of the normal and reverse magnets, andmeans including a front con tact of the relay to connect the winding ofthe relay between the common wire and a mid terminal of said resistor toretain the relay picked up subsequent to an overload condition.

6. In combination, a reversible electric motor, a normal and a reversemagnet, a normal motor operating circuit including a front contact ofthe normal magnet, a reverse motor operating circuit including a frontcontact of the reverse magnet, an overload relay, 2. normal control wireconnected with one terminal of the winding of the normal magnet, areverse control wire connected with one terminal of the winding of thereverse magnet, means including a back contact of the relay to connectthe other terminal of each of said windings with a common return wire, acircuit controller operative to connect a direct current source betweeneither the normal or reverse control wire and the common wire, a firstresistor common to both of said motor circuits, means including a backcontact of the relay to connect the winding of the relay across saidresistor to pick up the relay when an overload current flows in a motorcircuit for interrupting the overloaded circuit by deenergizing thecorresponding magnet, a second resistor connected across said normal andreverse control wires, and means including a front contact of the relayto switch the winding of the relay to a mid terminal of said secondresistor and the common return wire for retaining the overloaded circuitopen.

'7. In combination, a reversible electric motor, a normal and a reversemagnet, a normal motor operating circuit including a front contact ofthe normal magnet, a reverse motor operating circuit including a frontcontact of the reverse magnet, an overload relay, a normal control wireconnected with one terminal of the winding of the normal magnet, areverse control wire connected with one terminal of the winding of thereverse magnet, means including a back contact of the relay to connectthe other terminal of each of'said windings with a common return wire, acircuit controller operative to connect a direct current source betweeneither the normal or reverse control wire and the common wire, a firstresistor common to both of said motor circuits, means including a backcontact of the relay to connect the winding of the relay across saidresistor to pick up the relay when an overload current fiows in a motorcircuit for interrupting the overloaded circuit by deenergizing thecorresponding magnet, a second and a third resistor connected with saidnormal and reverse control wires respectively, a first stick circuitmeans ineluding a front contact of the relay and said second resistor toconnect said winding of the relay between the normal control wire andthe common return wire, and a second stick circuit means including afront contact of the relay and said third resistor to connect saidwinding of the relay between the reverse control wire and the commonreturn wire.

8. In combination, a reversible electric motor, a normal and a reversemagnet, a normal motor operating circuit including a front contact ofthe normal magnet, a reverse motor operating circuit including a frontcontact of the reverse magnet, an overload relay, a normal control wireconnected with one terminal of the winding of the normal magnet, areverse control wire connected with one terminal of the winding of thereverse magnet, means including a back contact of the relay to connectthe other terminal of each of said windings with a common return wire, acircuit controller operative to connect a direct current source betweeneither the normal or reverse control wire and the common wire, a firstresistor common to both of said motor circuits, means including a backcontact of the relay to connect the winding of the relay across saidresistor to pick up the relay when an overload cur rent flows in a motorcircuit for interrupting the 1- overloaded circuit by deenergizing thecorresponding magnet, a second and a third resistor connected with saidnormal and reverse control wires respectively, a first stick circuitmeans including a front contact of the relay and said second resistor toconnect said winding of the relay between the normal control wire andthe common return wire, and a second stick circuit means includinganother front contact of the relay and said third resistor to connectsaid winding of the relay between the reverse control wire and thecommon return wire.

BERNARD E. OHAGAN.

